Species is important but so is diet.
We shoot some species that you can’t, such as tundra swans. Early in the season they are eating aquatic life and taste like diving or sea ducks. Very hard to make them palatable. Three months later they have migrated 2000 miles and are on grain fields and are quite good if your shoot a young (grey) one.
As a general rule I class them like this - from worst to best
Sea ducks(shellfish in a summer bin for a week) then divers (pochards you would say) then teal/wigeon followed by large grain fed puddlers ( Mallard and Pintails).
Favorite way to eat a perfect mallard or pintail is to pluck then breast out as one piece. Marinate in cranberry juice for a few hours, then season. Put the meat side onto a hot grill to quickly sear, the slip a piece of fatty bacon in there and close it up with a tooth pick. Crisp the skin on both side on the same hot grill, serve pink in the center with a brown gravy with copious garlic.
For geese, we usually put snow geese at the bottom. Not truly fair, as a young snow is quite good, but old birds can be very old (they live up,to 20 years). Then canadas (and I think Greylags are equivalent - at least the ones I’ve eat ) followed by whitefronts (in my opinion pinks are about the same) .
For older tougher geese I will either serve as a kabob, after overnight marinade in pineapple and canned tomato + jalapeño. Season with a Greek style seasoning, then kabob with whatever else you like (petite potatoes, mushrooms, pepper, onion, cherry tomatoes). Drizzle all with olive oil and grill
For younger birds I either roast as a proper plucked bird, smoke, or if shot (or if I don’t feel like plucking) I’ll breast out and season with Mexican spices then grill before serving with sautéed onions and peppers as Fajitas on tortillas, with some fresh pico de gallo to accompany